Browsing by Author "Huang, Haibo"

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    Acetone, Butanol, and Ethanol (ABE) Production from Food Waste via Clostridium beijerinckii
    Poe, Nicholas Edward (Virginia Tech, 2020-01-28)
    Annually, approximately 150 million metric tonnes of food goes to waste in the U.S., potentially causing economic loss and environmental pollution. Fermentation of food waste to produce acetone, butanol and ethanol (ABE) via fermentation has the potential to valorize food waste by producing value-added chemicals. However, the composition of food wastes from different sources vary, which affects ABE fermentation performance and hinders the commercialization of food waste fermentation. The objective of this study is to investigate the compositional variation of food waste collected weekly for 16 weeks (a total of sixteen samples) and determine how this variation affects ABE fermentation performance. Samples collected from Southgate Center, a food processing facility operated by Virginia Tech Dining Services, was characterized for use as a feedstock for ABE fermentation. Water, sugar, starch, fiber, protein, fat and ash concentrations in each of food waste samples were determined. ABE fermentation of these wastes was performed using Clostridium beijerinckii via batch fermentations. Correlations of ABE and butanol yields with the individual components of food waste composition were performed to better understand which components are key to ABE fermentation. Overall, this study demonstrated the feasibility of using food waste as a viable feedstock for ABE fermentation and investigated the effect of variation of food waste composition on the ABE fermentation performance. In the 16 collected samples, each major compositional attribute exhibited high variability. The concentration of total soluble sugar, defined as glucose, fructose, sucrose for the purposes of this experiment, ranged from 0.5 to 53.5% (dry basis) among different food waste samples. The concentration ranges of total starch, neutral detergent fiber (NDF), crude protein, crude fat and ash were 0 to 23.4% (dry basis), 0.6 to 25.8%, 5.5 to 21.2%, 0.1 to 37.9%, 1.4 to 13.7%, respectively. The high variation of food waste composition resulted in a high variation of ABE yield when these food wastes were subjected to fermentation by C. beijerinckii. The total ABE concentration following fermentation ranged between 6.9 to 17.0 g/L with an average value of 13.2 g/L. ABE and butanol concentrations are positively correlated with starch and equivalent glucose, i.e., the sum of initial free glucose and glucose that could be theoretically hydrolyzed from starch and sucrose during fermentation, but is negatively correlated with NDF concentrations.
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    Acetone-butanol-ethanol (ABE) fermentation of soluble and hydrolyzed sugars in apple pomace by Clostridium beijerinckii P260
    Jin, Qing; Qureshi, Nasib; Wang, Hengjian; Huang, Haibo (2019-05-15)
    The decreasing supply of fossil fuels and increasing environmental concern of food waste disposal have raised interests in food waste conversation to biofuels such as butanol. Apple pomace, a food processing waste rich in carbohydrates, is a good feedstock for butanol production. The goal of this study is to present and evaluate a process to thoroughly convert apple pomace water soluble sugars (WSS) and hydrolyzed sugars from structural carbohydrates to acetone-butanol-ethanol (ABE) by fermentation. WSS was extracted from apple pomace by hot water. The solid residue was pretreated with acid or alkali followed by enzymatic hydrolysis to obtain acid hydrolyzed sugars (ACHS) or alkali hydrolyzed sugars (ALHS). Finally, WSS, ACHS, ALHS, WSS + ACHS, and WSS + ALHS were used as substrates to produce ABE by Clostridium beijerinckii P260, respectively. Acid and alkali pretreated apple pomace showed significantly (p < 0.05) higher glucose yield after cellulase hydrolysis compared with that of unpretreated apple pomace. Addition of pectinase increased hydrolyzed glucose yield by 27.9%, 26.9%, and 33.0% for acid pretreated sample, alkali pretreated sample, and unpretreated sample, respectively. Fermentation results revealed that inhibitors generated during pretreatment could negatively affect the ABE fermentation rate and titers; however, this negative effect could be alleviated by mixing the hydrolyzed sugars with water soluble sugars. A total of 202.8, 42.1, 41.4, 260.1, and 262.2 g of ABE was produced from each kg of dry apple pomace using WSS, ACHS, ALHS, WSS + ACHS, and WSS + ALHS as the substrates, respectively, based on the mass balance.
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    Can Xylose Be Fermented to Biofuel Butanol in Continuous Long-Term Reactors: If Not, What Options Are There?
    Qureshi, Nasib; Lin, Xiaoqing; Tao, Shunhui; Liu, Siqing; Huang, Haibo; Nichols, Nancy N. (MDPI, 2023-06-26)
    This study applied concentrated xylose (60–250 g/L) medium to produce butanol (acetone butanol ethanol, or ABE). A control batch fermentation of 61 g/L initial glucose using Clostridium beijerinckii P260 resulted in a productivity and yield of 0.33 g/L·h and 0.43 g/g, respectively. Use of 60 g/L xylose in a batch system resulted in productivity and yield of 0.26 g/L·h, and 0.40 g/g, respectively. In these two experiments, the culture fermented 89.3% glucose and 83.6% of xylose, respectively. When ABE recovery was coupled with fermentation for continuous solvent removal, the culture fermented all the added xylose (60 g/L). This system resulted in a productivity and yield of 0.66 g/L·h and 0.44 g/g, respectively. When the sugar concentration was further increased above 100 g/L, only a small fraction of the sugar was fermented in batch cultures without product removal. However, with simultaneous product removal, all the xylose (150 g/L) was fermented provided the culture was fed with nutrients intermittently. In this system, 66.32 g/L ABE was produced from 150 g/L xylose with a productivity of 0.44 g/L·h and yield of 0.44 g/g. Using the integrated culture system allowed sugar consumption to be increased by 300% (150 g/L). The continuous system using xylose as a feed did not sustain and after 36 days (864 h) of fermentation, it produced only 2–3 g/L ABE. Rather, the culture became acidogenic and produced 4–5 g/L acids (acetic and butyric). This study suggested that xylose be fermented in batch reactors coupled with simultaneous product recovery rather than in continuous reactors.
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    Chemical Compositions of Edamame Beans and Valorization of Edamame Shells
    Yu, Dajun (Virginia Tech, 2023-01-23)
    Edamame is becoming more popular in the U.S. due to its high nutritional value and potential health benefits. However, more than 70% of edamame is imported from outside of the U.S. Therefore, developing elite edamame genotypes is critically desirable to increase the domestic production of edamame in the U.S. Genotype, planting location, and harvest time play essential roles in the chemical composition of edamame, which further decide edamame's nutritional value and sensory characteristics. Therefore, the first goal of this study is to comprehensively evaluate the chemical composition of edamame genotypes grown in different locations. Ten selected edamame genotypes were grown in three locations in the U.S. - Whitethorne, Virginia (VA), Little Rock, Arkansas (AR) and Painter, VA. Sugars, alanine, protein, oil, neutral detergent fiber (NDF), starch, ash, and moisture contents, were comprehensively analyzed. The results showed that location had significant effects on all chemical components of edamame with p < 0.05. Compared to Painter and Little Rock, genotypes planted in Whitethorne had higher averaged free sucrose, fructose, glucose, raffinose, stachyose, and starch contents and total sweetness. The highest crude protein and oil contents were found on edamame planted in Painter, while Little Rock produced edamame with the highest free alanine, ash, and moisture contents. Genotype significantly affected chemical compositions except for NDF and raffinose. Therefore, planting location and edamame genotype should be considered when producing elite edamame for the U.S. market. Chemical composition changes with the development of edamame; therefore, harvest time is essential for harvesting high-quality edamame. The second objective of this study is to quantify the changes in both physical and chemical properties of edamame over bean development and apply a combined spectroscopy and machine learning (ML) technique to help determine the optimal harvest time. Physical and chemical properties were analyzed for edamame harvested at R5 (beginning seed), R6 (full seed), and R7 (beginning maturity) growth stages, and the spectral reflectance (360 – 740 nm) of edamame pods was measured using a handheld spectrophotometer. The samples harvested at different stages were labeled as 'early,' 'ready,' and 'late.' At R6, pod/bean weight and pod thickness reached the peak and then stayed stable, while sugar, alanine, starch, and glycine also peaked at R6 but declined afterward. The spectra-based ML method had high accuracy (0.95) when classifying 'early' and 'late' edamame, and the accuracy was 0.87 for classifying 'early' and 'ready' edamame. These results indicated that this spectra-based ML method could determine the optimal harvest time of edamame. Food waste and loss not only lead to economic loss but also significant greenhouse gas emissions. With edamame food/snack production increasing, edamame shells, the low-value byproduct from this processing, will potentially threaten the environment. Similar to other food processing byproducts, edamame shell is rich in dietary fiber (DF). However, the high concentration of insoluble dietary fiber (IDF) limits its application as a food additive. Therefore, extraction/modification processes are needed to convert IDF to soluble dietary fiber (SDF) and improve the properties of edamame shell-derived DF. Ball milling is one of the most efficient techniques to break down biomaterials into sub-micro-level particles. Citric acid, as a natural and safe food additive, can help break down cell walls and improve the dissolution of SDF by ionizing the hydrogen ions with carboxyl groups. Therefore, the third objective of this study is to develop a process that combines ball milling and citric acid treatments to produce SDF from edamame shells. We investigated different treatment parameters, including different citric acid concentrations, treatment temperatures and time, and the application of ball milling. To determine if the combined treatment can potentially improve the properties of the produced SDFs, we characterized the physicochemical, morphological, structural, rheological, thermal, and functional properties of SDFs produced at different conditions. The results showed that the highest SDF yield (19.5%) was found when the edamame shells were pretreated by a ball mill. In addition, the combined citric acid and ball milling treatment altered several properties of the produced SDFs, including particle size, morphology, and crystallinity. Moreover, ball milling treatment led to a higher exothermic temperature peak of SDF indicating better thermal stability. All produced SDFs significantly elevated the production of short-chain fatty acids during in vitro fermentation (compared to the control fermentation) which indicated their potential benefits of promoting gut health. Overall, we demonstrated that ball-milling-assisted citric acid processing can be an effective green technique to produce SDF from edamame shells. The SDF produced from edamame shells can be regarded as a promising and novel ingredient with great potential to be used in foods.
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    Chemical Compositions of Edamame Genotypes Grown in Different Locations in the US
    Yu, Dajun; Lin, Tiantian; Sutton, Kemper L.; Lord, Nick; Carneiro, Renata C. V.; Jin, Qing; Zhang, Bo; Kuhar, Thomas P.; Rideout, Steven L.; Ross, W. Jeremy; Duncan, Susan E.; Yin, Yun; Wang, Hengjian; Huang, Haibo (2021-02-12)
    The consumption of edamame [Glycine max (L.) Merr.] in the US has rapidly increased due to its nutritional value and potential health benefits. In this study, 10 edamame genotypes were planted in duplicates in three different locations in the US-Whitethorne, Virginia (VA), Little Rock, Arkansas (AR), and Painter, VA. Edamame samples were harvested at the R6 stage of the bean development when beans filled 80-90% of the pod cavity. Afterward, comprehensive chemical composition analysis, including sugars, alanine, protein, oil, neutral detergent fiber (NDF), starch, ash, and moisture contents, were conducted on powdered samples using standard methods and the total sweetness was calculated based on the measured sugars and alanine contents. Significant effects of the location were observed on all chemical constituents of edamame (p < 0.05). The average performance of the genotypes was higher in Whitethorne for the contents of free sucrose (59.29 mg/g), fructose (11.42 mg/g), glucose (5.38 mg/g), raffinose (5.32 mg/g), stachyose (2.34 mg/g), total sweetness (78.63 mg/g), and starch (15.14%) when compared to Little Rock and Painter. The highest soluble alanine (2.67 mg/g), NDF (9.00%), ash (5.60%), and moisture (70.36%) contents were found on edamame planted in Little Rock while edamame planted in Painter had the highest crude protein (43.11%) and oil (20.33%) contents. Significant effects of genotype were observed on most of the chemical constituents (p < 0.05) except NDF and raffinose. Among the 10 genotypes, R13-5029 consistently had high sucrose content and total sweetness across the three locations, meanwhile it had relatively high protein and fiber contents. Overall, the results indicate that to breed better edamame genotypes in the US, both genotype and planting location should be taken into considerations.
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    Compositional Characterization of Different Industrial White and Red Grape Pomaces in Virginia and the Potential Valorization of the Major Components
    Jin, Qing; O’Hair, Joshua; Stewart, Amanda C.; O'Keefe, Sean F.; Neilson, Andrew P.; Kim, Young Teck; McGuire, Megan N.; Lee, Andrew H.; Wilder, Geoffrey; Huang, Haibo (MDPI, 2019-12-11)
    To better evaluate potential uses for grape pomace (GP) waste, a comprehensive chemical composition analysis of GP in Virginia was conducted. Eight commercial white and red pomace samples (cv. Viognier, Vidal Blanc, Niagara, Petit Manseng, Petit Verdot, Merlot, Cabernet Franc, and Chambourcin) obtained from different wineries in Virginia, USA were used. For extractives, GPs contained 2.89%–4.66% titratable acids, 4.32%–6.60% ash, 4.62%–12.5% lipids with linoleic acid being the predominant (59.0%–70.9%) fatty acid, 10.4–64.8 g total phenolic content (gallic acid equivalents)/kg GP, 2.09–53.3 g glucose/kg GP, 3.79–52.9 g fructose/kg GP, and trace sucrose. As for non-extractives, GPs contained 25.2%–44.5% lignin, 8.04%–12.7% glucan, 4.42%–7.05% xylan, and trace amounts of galactan, arabinan, and mannan (less than 3% in total). Potential usages of these components were further examined to provide information on better valorization of GP. Considering the valuable extractives (e.g., polyphenols and oil) and non-extractives (e.g., lignin), designing a biorefinery process aiming at fully recover and/or utilize these components is of future significance.
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    Consumer responses and willingness-to-pay for hibiscus products: A preliminary study
    Ndiaye, Oumoule; Hedrick, Valisa E.; Neill, Clinton L.; Carneiro, Renata C. V.; Huang, Haibo; Fernandez-Fraguas, Cristina; Guiro, Amadou Tidiane; O'Keefe, Sean F. (Frontiers, 2023-04)
    The rise in diseases like obesity and diabetes is a worldwide challenge. The consumption of functional products such as hibiscus, which has been proven to be high in bioactive compounds and dietary fiber, providing it with anticancer, antiaging, anti-inflammatory and satiety properties, should be promoted. In the U.S., promoting the consumption of hibiscus products can be a good approach to increase fiber consumption and to reduce risk of obesity, diabetes, and hypertension. However, information about knowledge of this functional product among consumers is still sparse and increasing consumption requires designing and marketing desired products made from hibiscus. Therefore in this preliminary study, we assessed consumer response to hibiscus products and investigated whether providing information about potential health benefits could impact consumer willingness-to-pay (WTP) for three types of non-alcoholic hibiscus beverages: ready-made tea, bottled juice, and kombucha. Our web-based survey was distributed through Qualtrics(XM) and a convenience sampling method was chosen. Most participants identified themselves as female, 18-34 years old, with a graduate degree. Most participants (81%) had consumed hibiscus products before and 57% had a weekly food budget lower than $60. Overall, tea and juices were the most liked hibiscus beverages, respectively. Although taste and health benefits were ranked as the main reasons to consume hibiscus beverages, additional information about hibiscus health benefits did not significantly affect WTP for these products. Without additional health benefit information, consumer WTP for non-alcoholic hibiscus beverages ranged from $2.9 to $3.60 for kombucha and $4.08-4.97 for Ready-made-tea. This study provides valuable insights that can support future research on hibiscus products and promote the development of novel hibiscus-based foods and beverages that are appealing to the U.S. market.
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    Conversion of Food Waste into 2,3-Butanediol via Thermophilic Fermentation: Effects of Carbohydrate Content and Nutrient Supplementation
    Yu, Dajun; O’Hair, Joshua; Poe, Nicholas; Jin, Qing; Pinton, Sophia; He, Yanhong; Huang, Haibo (MDPI, 2022-01-10)
    Fermentation of food waste into 2,3-butanediol (2,3-BDO), a high-value chemical, is environmentally sustainable and an inexpensive method to recycle waste. Compared to traditional mesophilic fermentation, thermophilic fermentation can inhibit the growth of contaminant bacteria, thereby improving the success of food waste fermentation. However, the effects of sugar and nutrient concentrations in thermophilic food waste fermentations are currently unclear. Here, we investigated the effects of sugar and nutrients (yeast extract (YE) and peptone) concentrations on 2,3-BDO production from fermenting glucose and food waste media using the newly isolated thermophilic Bacillus licheniformis YNP5-TSU. When glucose media was used, fermentation was greatly affected by sugar and nutrient concentrations: excessive glucose (>70 g/L) slowed down the fermentation and low nutrients (2 g/L YE and 1 g/L peptone) caused fermentation failure. However, when food waste media were used with low nutrient addition, the bacteria consumed all 57.8 g/L sugars within 24 h and produced 24.2 g/L 2,3-BDO, equivalent to a fermentation yield of 0.42 g/g. An increase in initial sugar content (72.9 g/L) led to a higher 2,3-BDO titer of 36.7 g/L with a nearly theoretical yield of 0.47 g/g. These findings may provide fundamental knowledge for designing cost-effective food waste fermentation to produce 2,3-BDO.
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    Development and Characterization of a Pilot-Scale Model Cocoa Fermentation System Suitable for Studying the Impact of Fermentation on Putative Bioactive Compounds and Bioactivity of Cocoa
    Racine, Kathryn C.; Lee, Andrew H.; Wiersema, Brian D.; Huang, Haibo; Lambert, Joshua D.; Stewart, Amanda C.; Neilson, Andrew P. (MDPI, 2019-03-19)
    Cocoa is a concentrated source of dietary flavanols—putative bioactive compounds associated with health benefits. It is known that fermentation and roasting reduce levels of native flavonoids in cocoa, and it is generally thought that this loss translates to reduced bioactivity. However, the mechanisms of these losses are poorly understood, and little data exist to support this paradigm that flavonoid loss results in reduced health benefits. To further facilitate large-scale studies of the impact of fermentation on cocoa flavanols, a controlled laboratory fermentation model system was increased in scale to a large (pilot) scale system. Raw cocoa beans (15 kg) were fermented in 16 L of a simulated pulp media in duplicate for 168 h. The temperature of the fermentation was increased from 25–55 °C at a rate of 5 °C/24 h. As expected, total polyphenols and flavanol levels decreased as fermentation progressed (a loss of 18.3% total polyphenols and 14.4% loss of total flavanols during fermentation) but some increases were observed in the final timepoints (120–168 h). Fermentation substrates, metabolites and putative cocoa bioactive compounds were monitored and found to follow typical trends for on-farm cocoa heap fermentations. For example, sucrose levels in pulp declined from >40 mg/mL to undetectable at 96 h. This model system provides a controlled environment for further investigation into the potential for optimizing fermentation parameters to enhance the flavanol composition and the potential health benefits of the resultant cocoa beans.
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    Development of Cellulose-Titanium dioxide-Porphyrin Nanocomposite Films with High-barrier, UV-blocking, and Visible Light-Responsive Antimicrobial Features
    Lovely, Belladini (Virginia Tech, 2024-06-03)
    The packaging does not serve as a mere containment but also can be designed to play a key role in preserving the product from quality-deteriorating factors, including oxygen, light irradiation, and foodborne pathogenic microorganisms (e.g., Escherichia coli). There has been a growing interest in employing ultra-porous metal-organic frameworks (MOF) with visible light-responsive antibacterial mechanisms to generate reactive oxygen species (ROS) that can eliminate bacteria via an oxidative burst. MOF is made of inorganic metal ions/nodes/clusters/secondary building units linked by organic bridge ligands, where titanium dioxide (TiO2) and tetrakis(4-carboxyphenyl)porphyrin) (TCPP) were selected for these components, respectively. TiO2 is an exceptional UV-A/B/C-blocker; meanwhile, TCPP dye performs a remarkable photocatalytic ability even under visible light, on top of its macro-heterocyclic structure that is ideal as a MOF linker. Both have good compatibility but suffer from the notorious tendency to self-quench/aggregate. The incorporation of MOF-based conjugates into a polymeric matrix, like cellulose, is among the proven-successful solutions. Cellulose is the Earth's most abundant and naturally biodegradable, and cellulose nanofibril (CNF) was particularly chosen for its high specific surface area and surface activity. However, a straightforward, cheap, and environmentally friendly approach of multicycle homogenization (0-25 passes) was conducted to solve neat cellulose's challenge of natural hydrophilicity, where low pressure (<10 MPa) was applied to prevent the common over-shearing effect. The antibacterial efficacy of CNF films functionalized with TiO2-TCPP conjugate on inhibiting E. coli growth was analyzed with and without light of different intensities (3000 and 6000 lux). The positive impacts of CNFs' promoted fibrillation and subsequent inter/intra-molecular hydrogen bonding post-homogenization were evidenced in an array of functional properties, i.e., crystallinity, TiO2-TCPP conjugate dispersion, surface smoothness, mechanical properties, thermal stability, hydrophobicity, oxygen barrier (comparable to ethylene-vinyl alcohol (EVOH), a commercial high-barrier polymer), and 100%-antibacterial rate (under 6000 lux after 72 hours). Varying optimum cycles of homogenization demonstrated the prospect of the proposed homogenization approach in preparing CNF with diverse processability and applicability. These findings also exhibited a promising potential for a myriad of high-barrier, UV-blocking, and/or visible light-responsive antibacterial film applications, including food packaging and biomedical.
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    Edamame Processing: What Do I Need to Know?
    Carneiro, Renata; Yu, Dajun; Huang, Haibo; O’Keefe, Sean F.; Duncan, Susan (Virginia Cooperative Exension, 2020-06-18)
    This publication covers important aspects of edamame processing in order to inform and guide growers and food processors interested in this vegetable crop.
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    Effects of Hydroxycinnamates and Exogenous Yeast Assimilable Nitrogen on Cider Aroma and Fermentation Performance
    Cairns, Paulette Anne (Virginia Tech, 2019-07-08)
    Heritage apple cultivars for cider-making are often distinguished by a high concentration of tannins (phenolic compounds), and/or acid. The phenolic content of some cider apples far exceeds that of white wine, however most cider fermentation practices are directly taken from white winemaking, not accounting for effects of high concentrations of phenolic compounds on yeast fermentation. The objective of this study was to determine the impact of ferulic acid, p-coumaric acid, and chlorogenic acid—at concentrations reported in apples—and their interactions with yeast assimilable nitrogen (YAN) on fermentation kinetics and cider aroma. Our hypothesis was that the phenolic compounds present in high-tannin cider apples would negatively impact fermentation kinetics, but not alter the aroma, and that added YAN would reduce these effects. Ferulic acid negatively affected fermentation performance (p < 0.05), but p-coumaric acid and chlorogenic acid did not. p-Coumaric acid led to the greatest changes in cider aroma. Differences were also detected for different concentrations of ferulic acid. Chlorogenic acid did not affect aroma. Yeast strain influenced fermentation performance and cider aroma. Finally, addition of exogenous YAN improved fermentation performance for the low concentration ferulic acid condition, but not for the high concentration. Adding YAN also changed cider aroma in the presence of p-coumaric acid.
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    Ethanol Mist to Control Salmonella enterica serovar Newport on Fresh Tomato and Cantaloupe Surfaces
    Wesolowski, Michael Christopher (Virginia Tech, 2019-06-28)
    Water used in fresh produce washing is a potential vehicle of foodborne pathogen contamination. This work focused on assessing the sanitizing efficacy of ethanol mist to reduce Salmonella populations on the surfaces of tomatoes and cantaloupes. Ethanol (70%) mist was applied to whole tomatoes and cantaloupe rind plugs using a Biomist sanitation system, which uses CO2 as a carrier gas to spray vapors through a fine droplet spray nozzle. Fresh red tomatoes (Solanum lycopersicum) and cantaloupe (Cucumis melo) plugs were inoculated with Salmonella enterica Newport to a concentration of log 7 CFU/tomato and log 7 CFU/cm2 respectively. Application time (5, 10, and 15 sec), dry vs. wet surface, and stem scar contamination were evaluated on tomatoes, while only application time was evaluated on cantaloupe. Application of ethanol mist for 10 seconds was the most effective treatment time, reducing Salmonella by 3.3 log CFU/tomato. Application of ethanol mist was more effective on dry opposed to wet tomato surfaces by approximately 0.7 log CFU/tomato. Ethanol mist application to inoculated tomato stem scars reduced Salmonella 1.2 log CFU/tomato. Additionally, Salmonella decreased by 1.3 log CFU/cm2 on cantaloupe rind plugs at 10 seconds, again the most effective treatment time. Ethanol mist resulted in sufficient reductions of Salmonella populations on dry tomato surfaces, but was limited in effectiveness if the surface was wet, or if Salmonella adhered to the stem scar. Furthermore, this technique was overall not an efficient method to sanitize cantaloupe surfaces.
  • Evaluating Pediococcus acidilactici and Enterococcus faecium NRRL B-2354 as Surrogates for Salmonella enterica on Low Temperature Saturated Steam Pasteurized Cashews and Macadamia Nuts
    Saunders, Thomas P.; Wu, Jian; Williams, Robert C.; Huang, Haibo; Ponder, Monica A. (2023-02)
    Low temperature saturated steam pasteurization reduces numbers of Salmonella enterica on macadamia nuts and cashews. Lethality of pasteurization must be verified necessitating identification of non-pathogenic surrogates. Whole cashews and macadamia nuts were co-inoculated with S. enterica and one of three potential surrogates (Enterococcus faecium, Pediococcus acidilactici, and Staphylococcus carnosus) then dried to original water activity (aw) around 0.44 - 0.51. Nuts were packaged in woven polypropylene bags and commercially processed using saturated steam at 85 ± 5°C. Bacteria were enumerated by plating onto TSA with an overlay of XLT-4 for Salmonella, or on media selective for the potential surrogates. Mean reduction (log CFU·g-1) of Salmonella (6.0 ± 0.14) was significantly larger than E. faecium (4.3± 0.12), or P. acidilactici (3.7± 0.14) on cashews. Mean reduction of Salmonella (5.9 ± 0.18) was significantly larger than P. acidilactici (4.4± 0.18) on macadamia nuts, but instances occurred where E. faecium reduction on macadamia nuts exceeded Salmonella. St.carnosus reduction exceeded that of Salmonella and is therefore not an appropriate surrogate. Based on these studies caution should be applied when choosing a surrogate for different types of nuts, as acceptability of E. faecium as a surrogate for Salmonella varied between cashews and macadamia nuts.
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    Evaluation of cocoa (Theobroma cacao) bean processing strategies to enhance alpha-glucosidase inhibitory activity of dietary cocoa
    Racine, Kathryn Claire (Virginia Tech, 2019-06-18)
    Cocoa beans (Theobroma cacao) are a highly concentrated source of dietary flavanols- bioactive compounds associated with the health protective properties of cocoa. Cocoa beans undergo processing steps, such as fermentation, roasting, winnowing, grinding, pressing, etc., to produce a final product with specific desirable sensory attributes. It is well established that these processing steps, specifically fermentation and roasting, result in dramatic degradation of cocoa's native flavanols, but it is possible that these processing steps may generate compounds with novel activities, potentially preserving or enhancing bioactivity. Raw unfermented cocoa beans were processed by way of a partial factorial approach to produce cocoa powders from the same batch of raw beans using various combinations of fermentation [unfermented, cool fermented (maximum 46°C), hot fermented (maximum 60°C))] and roasting [unroasted, cool roasted (120°C), hot roasted (170°C)]. To simulate cocoa fermentation in a highly controlled environment, a pilot-scale fermentation model system was employed to eliminate many external unknowns and ensure that the differences between our cocoa powders were due to our various treatments, rather than unknown factors occurring during fermentation and roasting. Low and high molecular weight fractions (8-10 kDa cutoff) were produced from cocoa powder extracts (CPE) of each treatment to quantify Maillard reaction products (MRP). A HILIC-UPLC MS/MS method was developed to more efficiently and sensitively quantify cocoa flavanols with high degrees of polymerization (DP) produced during processing. Overall, cocoa processing significantly (p<0.05) decreased the total phenolic and total flavanol concentrations of CPEs. Hot roasting had the greatest impact on native flavanol degradation yet produced CPEs with the highest mean degree of polymerization (mDP). All CPEs dose-dependently inhibited α-glucosidase enzyme activity, with cool fermented/cool roasted cocoa powder exhibiting the best inhibition (IC50 of 62.2 µg/mL). Increasing flavanol mDP was correlated with decreasing IC50 values, suggesting that the complex flavanols produced during processing enhance cocoa's bioactivity (or their production is associated with other products that enhance bioactivity). Alternatively, high molecular weight CPE fractions were correlated with increasing IC50 values, suggesting that MRPs interfere with enzyme inhibition or are associated with other products (polyphenols, macronutrients, etc.) that interfere with enzyme inhibition. Overall, the data presented within this work indicate that the components of processed cocoa powders are promising inhibitors of α-glucosidase, despite a significant reduction in native flavanol composition induced by processing, and moreover that fermentation and roasting conditions can positively influence the bioactivity of cocoa despite losses of native flavanols.
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    Evaluation of the quantity and composition of sugars and lipid in the juice and bagasse of lipid producing sugarcane
    Huang, Haibo; Moreau, Robert A.; Powell, Michael J.; Wang, Zhaoqin; Kannan, Baskaran; Altpeter, Fredy; Grennan, Aleel K.; Longe, Stephen P.; Singh, Vijay (2017-04)
    Biodiesel production in the U.S. from vegetable oils has increased substantially during the past decade. However, its further increase is limited by the low amounts of oil produced per hectare from temperate oilseed crops. Recently novel transgenic sugarcane has been developed to accumulate both sugars and lipids in stems, making it a promising dual-purpose feedstock to produce both ethanol and biodiesel. In this study, two lines of the transgenic lipid producing sugarcane (lipid-cane) and the non-transformed sugarcane were characterized and processed. The total lipid concentrations were 0.7%, 0.9% and 1.3% for the non-transformed sugarcane and lipid-cane lines19B and 25 C, respectively. Lipid composition analysis showed that about 31-33% of the total lipids were triacylglycerols, main feedstock for biodiesel production, for the lipid-cane samples, while this value was only 5% for the non-transformed sugarcane. By processing the sugarcane stems with a juicer, about 90% of the sugars and 60% of the lipids were extracted with juice. The extracted sugars in juice were fermented to ethanol and the lipids were later recovered from the fermented juice using organic solvents. The recovered lipids from the fermented juice were 0.3, 0.5 and 0.8 g/100 g dry stem for the non-transformed sugarcane and lipid-cane lines 19B and 25 C, respectively. This study proved the concept of the lipid and sugar coproduction from the novel lipid-cane, which have a potential to make a large-scale replacement of fossil derived fuel without unrealistic demands on land area.
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    Feasibility of using Waste Heat as a power source to operate Microbial Electrolysis Cells towards Resource Recovery
    Jain, Akshay (Virginia Tech, 2020-05-05)
    Wastewater treatment has developed as a mature technology over time. However, conventional wastewater treatment is a very energy-intensive process. Bioelectrochemical system (BES) is an emerging technology that can treat wastewater and also recover resources such as energy in the form of electricity/hydrogen gas and nutrients such as nitrogen and phosphorus compounds. Microbial electrolysis cell (MEC) is a type of BES that, in the presence of an additional voltage, can treat wastewater and generate hydrogen gas. This is a promising approach for wastewater treatment and value-added product generation, though it may not be sustainable in the long run, as it relies on fossil fuels to provide that additional energy. Thus, it is important to explore alternative renewable resources that can provide energy to power MEC. Waste heat is one such resource that has not been researched extensively, particularly at the low-temperature spectrum. This was utilized as a renewable resource by converting waste heat to electricity using a device called thermoelectric generator (TEG). TEG converted simulated waste heat from an anaerobic digester to power an MEC. The feasibility of TEG to act as a power source for an MEC was investigated and its performance compared to the external power source. Various cold sources were analyzed to characterize TEG performance. To explore this integrated TEG-MEC system further, a hydraulic connection was added between the two systems. Wastewater was used as a cold source for TEG and it was recirculated to the anode of the MEC. This system showed improved performance with both systems mutually benefitting each other. The operational parameters were analyzed for the optimization of the system. The integrated system could generate hydrogen at a rate of 0.36 ± 0.05 m3 m-3 d-1 for synthetic domestic wastewater treatment. For the practical application, it is necessary to estimate the cost and narrow the focus on the functions of the system. Techno-economic analysis was performed for MEC with cost estimation and net present value model to understand the economic viability of the technology. The application niche of the BES was described and directions for addressing the challenges towards a full-scale operation were discussed. The present system provides a sustainable method for wastewater treatment and resource recovery which can play an important role in human health, social and economic development and a strong ecosystem.
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    Flavor and Quality Characteristics of Two Primocane-bearing Blackberry Cultivars as Impacted by Foliar and Shade Application
    Xu, Tianyou (Virginia Tech, 2023-07-28)
    Blackberry (Rubus spp.) is a popular fruit due to its delightful taste and notable health benefits. With a growing demand for regional blackberry production, this study aims to provide Virginia blackberry growers with information on the effectiveness of pre-harvest foliar treatments and shade application on yield, white drupelet disorder, post-harvest attributes, and the aroma profile of two blackberry cultivars, Prime-Ark® Traveler and Prime-Ark® Freedom. The field study was repeated in the 2021 and 2022 growing seasons at the Hampton Roads Agricultural Research and Extension Center in Virginia Beach, VA, in a completely randomized design. Grower standard control (GSC), shade cloth with 30% light reduction (SHA), calcium (CAL), and salicylic acid (SAL) foliar applications were randomly assigned to each variety. Fruit yield and physicochemical attributes of the blackberry were collected and analyzed, and aroma-active compounds in blackberries were identified by use of headspace-solid-phase microextraction-gas chromatography-mass spectrometry-olfaction (HS-SPME-GC-MS-O). Shade cloth significantly reduced the white drupelet disorder (WDD) in Prime-Ark® Freedom but it also reduced the total soluble solid content (°Bx) and °Bx/% titratable acidity (a ratio indicates the sweet and sour balance for fruit) for both cultivars. No significant improvement was found in the TSS, TA, firmness and yield of blackberries treated with CAL and SAL. In total, 16 consistent aroma-active compounds were found across treatments for both varieties and growing seasons. Foliar and shade application did not alter the aroma profile of either blackberry cultivar. However, higher volatile contents were found in 2021 than in 2022, possibly due to climate variation. A clear distinction on aroma profiles of the above two cultivars were also observed: PrimeArk® Freedom was higher in compounds possessing "fruity" and "floral" notes, while PrimeArk® Traveler featured more "green" and "fresh" characteristics. Regional berry growers should be more conservative when adopting foliar and shade applications due to potential seasonal variations surpassing the significance of agronomic treatments.
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    Food Waste from Campus Dining Hall as a Potential Feedstock for 2,3-Butanediol Production via Non-Sterilized Fermentation
    Caldwell, Alicia; Su, Xueqian; Jin, Qing; Hemphill, Phyllicia; Jaha, Doaa; Nard, Sonecia; Tiriveedhi, Venkataswarup; Huang, Haibo; OHair, Joshua (MDPI, 2024-01-31)
    Food waste is a major issue that is increasingly affecting our environment. More than one-third of food is wasted, resulting in over $400 billion in losses to the U.S. economy. While composting and other small recycling practices are encouraged from person-to-person, it is not enough to balance the net loss of 80 million tons per year. Currently, one of the most promising routes for reducing food waste is through microbial fermentation, which can convert the waste into valuable bioproducts. Among the compounds produced from fermentation, 2,3-butanediol (2,3-BDO) has gained interest recently due to its molecular structure as a building block for many other derivatives used in perfumes, synthetic rubber, fumigants, antifreeze agents, fuel additives, and pharmaceuticals. Waste feedstocks, such as food waste, are a potential source of renewable energy due to their lack of cost and availability. Food waste also possesses microbial requirements for growth such as carbohydrates, proteins, fats, and more. However, food waste is highly inconsistent and the variability in composition may hinder its ability to be a stable source for bioproducts such as 2,3-BDO. This current study focuses specifically on post-consumer food waste and how 2,3-BDO can be produced through a non-model organism, Bacillus licheniformis YNP5-TSU during non-sterile fermentation. From the dining hall at Tennessee State University, 13 food waste samples were collected over a 6-month period and the compositional analysis was performed. On average, these samples consisted of fat (19.7%), protein (18.7%), ash (4.8%), fiber (3.4%), starch (27.1%), and soluble sugars (20.9%) on a dry basis with an average moisture content of 34.7%. Food waste samples were also assessed for their potential production of 2,3-BDO during non-sterile thermophilic fermentation, resulting in a max titer of 12.12 g/L and a 33% g/g yield of 2,3-BDO/carbohydrates. These findings are promising and can lead to the better understanding of food waste as a defined feedstock for 2,3-BDO and other fermentation end-products.
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    Genome-wide association analysis of sucrose and alanine contents in edamame beans
    Wang, Zhibo; Yu, Dajun; Morota, Gota; Dhakal, Kshitiz; Singer, William; Lord, Nilanka; Huang, Haibo; Chen, Pengyin; Mozzoni, Leandro; Li, Song; Zhang, Bo (Frontiers, 2023-02-03)
    The sucrose and Alanine (Ala) content in edamame beans significantly impacts the sweetness flavor of edamame-derived products as an important attribute to consumers' acceptance. Unlike grain-type soybeans, edamame beans are harvested as fresh beans at the R6 to R7 growth stages when beans are filled 80-90% of the pod capacity. The genetic basis of sucrose and Ala contents in fresh edamame beans may differ from those in dry seeds. To date, there is no report on the genetic basis of sucrose and Ala contents in the edamame beans. In this study, a genome-wide association study was conducted to identify single nucleotide polymorphisms (SNPs) related to sucrose and Ala levels in edamame beans using an association mapping panel of 189 edamame accessions genotyped with a SoySNP50K BeadChip. A total of 43 and 25 SNPs was associated with sucrose content and Ala content in the edamame beans, respectively. Four genes (Glyma.10g270800, Glyma.08g137500, Glyma.10g268500, and Glyma.18g193600) with known effects on the process of sucrose biosynthesis and 37 novel sucrose-related genes were characterized. Three genes (Gm17g070500, Glyma.14g201100 and Glyma.18g269600) with likely relevant effects in regulating Ala content and 22 novel Ala-related genes were identified. In addition, by summarizing the phenotypic data of edamame beans from three locations in two years, three PI accessions (PI 532469, PI 243551, and PI 407748) were selected as the high sucrose and high Ala parental lines for the perspective breeding of sweet edamame varieties. Thus, the beneficial alleles, candidate genes, and selected PI accessions identified in this study will be fundamental to develop edamame varieties with improved consumers' acceptance, and eventually promote edamame production as a specialty crop in the United States.